OIDC meaning
OIDC, or OpenID Connect, is an authentication protocol built on top of OAuth 2.0. It enables applications to verify a user’s identity based on information given by an identity provider (such as Google or Microsoft) and to obtain basic profile details in a secure way. Unlike simple logins, OIDC provides a standardized process that lets users access multiple services with a single set of user credentials, reducing password fatigue while improving overall user authentication security.
OIDC examples
You may not notice it, but OIDC is behind many of the login buttons you see every day. When you click “Sign in with Google,” “Continue with Apple,” or “Log in with Microsoft,” the application relies on an OpenID provider to authenticate users and confirm their identity.
The provider works with an authorization server to issue an ID token and sometimes an access token, which the app uses to complete the login.
Popular platforms that use the OpenID Connect protocol include:
- Google — the most widely recognized OpenID provider.
- Microsoft Azure Active Directory — used by businesses for secure single sign-on.
- Apple ID — built into devices and apps across the Apple ecosystem.
- Amazon Cognito — helps developers add user authentication to apps and websites.
These integrations make it possible for millions of people to access services without creating new passwords, while giving developers a trusted way to confirm identity.
How does OIDC work?
OIDC works by connecting an application with an identity provider to verify a user’s identity. The process involves tokens, scopes, and an authorization server that coordinates the login.
The authentication flow typically follows these steps:
- 1.User login. The user clicks “Sign in with Google” (or another provider) on an app or website.
- 2.Authorization request. The app redirects the user to the authorization server of the chosen provider, which manages the authentication process.
- 3.User authentication. The provider verifies the user’s identity by checking their credentials.
- 4.Scopes and consent. The app requests certain scopes (such as email address or profile information), and the user may be asked to approve sharing that data.
- 5.Token exchange. Once approved, the provider issues an ID token (used to identify the user) and sometimes an access token (used to access resources). This step is known as token-based authentication.
- 6.Application access. The app receives the tokens, validates them, and grants the user access without needing a separate account or password.
This flow makes user authentication more secure and flexible, while also significantly reducing the number of passwords users need to manage.
What are the main components of OIDC?
The OpenID Connect protocol involves three main components that work together to complete the authentication process:
- End user — the person who wants to log in to an application.
- OpenID provider — the trusted service, like Google or Microsoft, that verifies the user’s identity through its authorization server.
- Relying party — the application or website that relies on the provider to authenticate users and grant access.
These three parts communicate through ID tokens and sometimes access tokens, making it possible for users to sign in securely with the same identity across different platforms.
What are the OIDC flows?
OIDC offers different “flows,” or login patterns, that describe how tokens are exchanged between the app or website, the OpenID provider, and the user. Each flow defines the steps an application takes to authenticate users and request the right type of token, such as an ID token for identity or an access token for protected resources. The most common option is the authorization code flow, but other flows exist to suit different devices, apps, and security needs.
OIDC authorization code flow
The authorization code flow is the most common and secure way to use OIDC. The application receives an authorization code from the authorization server, then exchanges it for an ID token and an access token to authenticate the user. This method is widely recommended for web and mobile apps that need strong protection.
Implicit flow
The implicit flow was designed for browser-based apps that cannot safely store a client secret. Tokens are returned directly to the application without an extra exchange, which makes it faster but less secure. Because of these security risks, implicit flow is less common today and often replaced by other flows.
Hybrid flow
The hybrid flow combines elements of both the authorization code and implicit flows. It lets the application receive some tokens right away while still using a code exchange for added security. This exact balance makes it useful for apps that need both speed and reliability.
Client credentials flow
Client credentials flow is used when an application needs to authenticate itself rather than a user. In this case, the app communicates with the OpenID provider to get an access token, which it uses to connect securely to protected resources. Client credentials flow is commonly used for server-to-server communication.
Device code flow
The device code flow is used for devices without a browser or keyboard, like smart TVs or consoles. The user enters a code on another device, and the application later receives an ID token once the provider verifies the login. Such a process allows limited-input devices to provide secure authentication without complex setups.
What are the benefits of OpenID Connect?
At its core, OpenID Connect offers a standard, secure, and user-friendly way to handle identity across multiple apps, solving many pain points in traditional authentication. The biggest advantage is that it lets applications offload identity work to trusted providers, reducing risk while making access simpler.
Benefits for users
Users benefit from OIDC because it makes login faster, safer, and less frustrating. Instead of juggling dozens of passwords, they can rely on trusted providers to confirm who they are.
- Simplified authentication process. Users can sign in with an existing account (such as Google or Microsoft) instead of creating new logins on each site.
- Fewer passwords to manage. There’s no need to create countless passwords for different websites or apps.
- Improved user experience. Logging into apps or websites on phones, laptops, or tablets is simple and consistent.
- More trust in apps. Signing in with trusted providers worldwide, such as Google or Microsoft, gives users more confidence that their data is safe.
Benefits for developers and businesses
For developers and businesses, OIDC lets apps skip storing passwords and focus on security, user experience, and scalability. It also supports flexible integration with other modern security standards.
- Stronger security. By relying on an OpenID provider and using tokens, OIDC reduces the risk of stolen credentials. OIDC can also be paired with multi-factor authentication to add another layer of protection.
- Built-in interoperability. OIDC is built on OAuth 2.0, so it fits well into modern API ecosystems and works on different platforms.
- Lower abandonment rates. Easier login flows tend to keep users from abandoning registration or checkout processes.
- Simplified integrations. Many identity providers already support OIDC, so developers can join existing infrastructure faster.
- Granular control and scopes. Apps can request only the user data they need (via scopes), supporting privacy and compliance.
- Scalable identity management. As a system grows, OIDC can support more users and services without reinventing the authentication wheel.
What are the differences between SAML, OAuth 2.0, and OIDC?
OIDC authentication, OAuth 2.0, and SAML all manage secure access between services. The difference is in their approach to handling tokens, the types of data exchanged, and the authentication vs. authorization methods used. While OIDC is the most modern and lightweight, OAuth 2.0 is focused on authorization, and SAML is often used in enterprise settings for single sign-on (SSO).
OIDC vs. SAML
OIDC vs. SAML comes down to flexibility and format. OIDC is a newer decentralized authentication protocol built on OAuth 2.0, while SAML (security assertion markup language) is an older XML-based standard. OIDC uses JSON and lightweight tokens for user identity verification, making it better suited for modern apps and APIs. SAML, on the other hand, is common in business tools and still widely used for business SSO.
OIDC vs. OAuth 2.0
OAuth 2.0 is focused on authorization, which controls what a user is allowed to do inside an app. It doesn’t verify identity. OIDC builds on this framework by adding an identity layer for authentication, issuing an ID token that verifies who the user is and may include profile details like a name or email.
SAML vs. OIDC vs. OAuth
Let’s look at how each standard differs and what similarities they share in a side-by-side comparison:
| Feature | OIDC (OpenID Connect) | OAuth 2.0 | SAML |
|---|---|---|---|
| Purpose | Authentication | Authorization | Authentication and authorization |
| Format | JSON web tokens (ID token, access token, refresh token) | JSON, tokens (access token, refresh token) | XML assertions |
| Data provided | Basic user profile information (like email, name) | Limited to access permissions and scopes | Detailed identity attributes |
| Best suited for | Modern apps, mobile, APIs | Granting apps limited access to resources | Enterprise single sign-on (SSO) |
| Example use | “Sign in with Google” for an app | Allowing an app to access your calendar | Logging into multiple corporate apps with one account |
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